Email is generally used as a means of communicating between individuals via a public network. Recently, exchanging an email attached with image data or music data is also gaining popularity.
When sending an email from a mobile phone, certain charges are imposed according to the quantity of data transmitted. Therefore, when sending an email attached with image data or music data, the communication costs are high because the data itself is large in quantity.
Furthermore, when receiving an email attached with image data or music data by mobile phone, since the data itself is large in quantity, storing all the image data or music data is difficult.